The 2003 Medicare Modernization Act (MMA) provides several new advantages to Medicare Advantage (MA) plans including increasing payments for more medically complex and frail beneficiaries and allowing plans to restrict care to networks of providers. This has stimulated a doubling of the MA population among nursing home (NH) residents over the past 10 years. However, very little is known about NH care for MA patients, such as the quality of NHs patients are admitted to, the outcomes of that NH care, or drivers of variations in care. The absence of this information prohibits Medicare beneficiaries and their families from choosing MA plans and NHs in an informed manner, and discourages competition between MA plans. In addition, this lack of knowledge compromises our ability to understand the implications of expansions of special needs and dual eligible MA plans included in the Affordable Care Act (ACA). The objective of this application is to assemble and analyze national data to assess quality of the NHs used by MA patients, and the health outcomes that MA patients experience. The central hypothesis of this proposal is that better managed care yields careful and efficient NH placements that improve health outcomes of MA patients. This hypothesis is based on two main observations. First, since there is good empirical evidence that NH quality affects patients' health care utilization like hospitalization and NH length of stay, capitated payment mechanism gives MA plans large incentives to steer patients to high quality SNFs. Second, concentration of patients in a NH from a particular MA plan increases the ability of MA medical staff, physicians and nurse practitioners, to monitor residents' condition efficientl allowing integration of different types of care providers and better coordination that positively affects patient outcomes. To achieve these objectives, we propose two Aims: 1) to compare the quality of NH that MA and FFS patients enter after controlling for distances of alternative NHs from patients' residential neighborhoods; and 2) to estimate the impact of concentration of MA plans in a nursing home on patients' hospitalization, nursing home length of stay and mortality. We propose to study MA and FFS Medicare beneficiaries newly admitted to NHs in 2013 in the US, integrating three data sources: Medicare enrollment records, individual level HEDIS utilization data and the mandatory NH resident assessment minimum data set (MDS 3.0). The expected outcomes of this work are novel data about where MA patients needing NH care are treated, the quality of that care, and care outcomes. The growth of MA plans and the increasing use of nursing facilities for post-acute care, makes it imperative we understand how and where MA plans are serving their frail and vulnerable members who become permanent residents.